The present invention relates to a machine tool in which there are fewer restrictions on the size of a workpiece that is workable thereon.
Machine tools provided with a spindle, a spindle motor, a redution gear and a longitudinal feed gear in general use include a bench drilling machine. It is also known to mount a workhead having the above-mentioned elements on an upright column so as to be elevatable and movable around the axis of the column. As occasion demands, the machine tool may be provided with an indexing attachment so that the workhead can be moved around an axis perpendicular to the axis of the spindle and/or with a horizontal arm for facilitating horizontal movement of the workhead in order to provide greater freedom in the working position of the workhead.
The trouble is that each of the conventional machine tools of this type has only one worktable with a specific height, resulting in that the size of a workpiece workable thereon is restricted to within comparatively narrow limits. The workpiece workable thereon is limited to a workpiece which can be set between a tip of a tool clamped on the spindle and the worktable with the workhead in its uppermost position.